The algorithm for determining offensiveness seems to have many variables and is much, much more than just language:

the use of negative words suck as 'sucks' or 'terrible'

account-wide penalty. Some accounts will have all their tweets marked as offensive no matter where they post or what they post

some accounts,especially well-known verified accounts, will have a much lower threshold for tweets to be marked as offensive, regardless of language.

tweets that contain images, videos, and or links at much higher risk of being marked as offensive

tweets from new accounts and or accounts with few followers more likely to be marked as offensive

tweets with links from certain domains and or host IPs will be marked as offensive

IP of the twitter account user and or where it was created

a tweet with preview text from a link that contains certain content will be market as offensive